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Diffstat (limited to 'libjava/java/lang/Thread.java')
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diff --git a/libjava/java/lang/Thread.java b/libjava/java/lang/Thread.java deleted file mode 100644 index 8b6d4ba..0000000 --- a/libjava/java/lang/Thread.java +++ /dev/null @@ -1,1358 +0,0 @@ -/* Thread -- an independent thread of executable code - Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 - Free Software Foundation - -This file is part of GNU Classpath. - -GNU Classpath is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU Classpath is distributed in the hope that it will be useful, but -WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GNU Classpath; see the file COPYING. If not, write to the -Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 USA. - -Linking this library statically or dynamically with other modules is -making a combined work based on this library. Thus, the terms and -conditions of the GNU General Public License cover the whole -combination. - -As a special exception, the copyright holders of this library give you -permission to link this library with independent modules to produce an -executable, regardless of the license terms of these independent -modules, and to copy and distribute the resulting executable under -terms of your choice, provided that you also meet, for each linked -independent module, the terms and conditions of the license of that -module. An independent module is a module which is not derived from -or based on this library. If you modify this library, you may extend -this exception to your version of the library, but you are not -obligated to do so. If you do not wish to do so, delete this -exception statement from your version. */ - -package java.lang; - -import gnu.classpath.VMStackWalker; -import gnu.gcj.RawData; -import gnu.gcj.RawDataManaged; -import gnu.java.util.WeakIdentityHashMap; - -import java.lang.management.ManagementFactory; -import java.lang.management.ThreadInfo; -import java.lang.management.ThreadMXBean; - -import java.util.HashMap; -import java.util.Map; - -import java.lang.reflect.InvocationTargetException; -import java.lang.reflect.Method; - -/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 - * "The Java Language Specification", ISBN 0-201-63451-1 - * plus online API docs for JDK 1.2 beta from http://www.javasoft.com. - * Status: Believed complete to version 1.4, with caveats. We do not - * implement the deprecated (and dangerous) stop, suspend, and resume - * methods. Security implementation is not complete. - */ - -/** - * Thread represents a single thread of execution in the VM. When an - * application VM starts up, it creates a non-daemon Thread which calls the - * main() method of a particular class. There may be other Threads running, - * such as the garbage collection thread. - * - * <p>Threads have names to identify them. These names are not necessarily - * unique. Every Thread has a priority, as well, which tells the VM which - * Threads should get more running time. New threads inherit the priority - * and daemon status of the parent thread, by default. - * - * <p>There are two methods of creating a Thread: you may subclass Thread and - * implement the <code>run()</code> method, at which point you may start the - * Thread by calling its <code>start()</code> method, or you may implement - * <code>Runnable</code> in the class you want to use and then call new - * <code>Thread(your_obj).start()</code>. - * - * <p>The virtual machine runs until all non-daemon threads have died (either - * by returning from the run() method as invoked by start(), or by throwing - * an uncaught exception); or until <code>System.exit</code> is called with - * adequate permissions. - * - * <p>It is unclear at what point a Thread should be added to a ThreadGroup, - * and at what point it should be removed. Should it be inserted when it - * starts, or when it is created? Should it be removed when it is suspended - * or interrupted? The only thing that is clear is that the Thread should be - * removed when it is stopped. - * - * @author Tom Tromey - * @author John Keiser - * @author Eric Blake (ebb9@email.byu.edu) - * @author Andrew John Hughes (gnu_andrew@member.fsf.org) - * @see Runnable - * @see Runtime#exit(int) - * @see #run() - * @see #start() - * @see ThreadLocal - * @since 1.0 - * @status updated to 1.4 - */ -public class Thread implements Runnable -{ - /** The minimum priority for a Thread. */ - public static final int MIN_PRIORITY = 1; - - /** The priority a Thread gets by default. */ - public static final int NORM_PRIORITY = 5; - - /** The maximum priority for a Thread. */ - public static final int MAX_PRIORITY = 10; - - /** - * The group this thread belongs to. This is set to null by - * ThreadGroup.removeThread when the thread dies. - */ - ThreadGroup group; - - /** The object to run(), null if this is the target. */ - private Runnable runnable; - - /** The thread name, non-null. */ - String name; - - /** Whether the thread is a daemon. */ - private boolean daemon; - - /** The thread priority, 1 to 10. */ - private int priority; - - boolean interrupt_flag; - - /** A thread is either alive, dead, or being sent a signal; if it is - being sent a signal, it is also alive. Thus, if you want to - know if a thread is alive, it is sufficient to test - alive_status != THREAD_DEAD. */ - private static final byte THREAD_DEAD = 0; - private static final byte THREAD_ALIVE = 1; - private static final byte THREAD_SIGNALED = 2; - - private boolean startable_flag; - - /** The context classloader for this Thread. */ - private ClassLoader contextClassLoader; - - /** This thread's ID. */ - private final long threadId; - - /** The next thread ID to use. */ - private static long nextThreadId; - - /** Used to generate the next thread ID to use. */ - private static long totalThreadsCreated; - - /** The default exception handler. */ - private static UncaughtExceptionHandler defaultHandler; - - /** Thread local storage. Package accessible for use by - * InheritableThreadLocal. - */ - ThreadLocalMap locals; - - /** The uncaught exception handler. */ - UncaughtExceptionHandler exceptionHandler; - - /** This object is recorded while the thread is blocked to permit - * monitoring and diagnostic tools to identify the reasons that - * threads are blocked. - */ - private Object parkBlocker; - - /** Used by Unsafe.park and Unsafe.unpark. Se Unsafe for a full - description. */ - static final byte THREAD_PARK_RUNNING = 0; - static final byte THREAD_PARK_PERMIT = 1; - static final byte THREAD_PARK_PARKED = 2; - static final byte THREAD_PARK_DEAD = 3; - - /** The access control state for this thread. Package accessible - * for use by java.security.VMAccessControlState's native method. - */ - Object accessControlState = null; - - // This describes the top-most interpreter frame for this thread. - RawData interp_frame; - - // This describes the top most frame in the composite (interp + JNI) stack - RawData frame; - - // Current state. - volatile int state; - - // Our native data - points to an instance of struct natThread. - RawDataManaged data; - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(null, null,</code> - * <i>gname</i><code>)</code>, where <b><i>gname</i></b> is - * a newly generated name. Automatically generated names are of the - * form <code>"Thread-"+</code><i>n</i>, where <i>n</i> is an integer. - * <p> - * Threads created this way must have overridden their - * <code>run()</code> method to actually do anything. An example - * illustrating this method being used follows: - * <p><blockquote><pre> - * import java.lang.*; - * - * class plain01 implements Runnable { - * String name; - * plain01() { - * name = null; - * } - * plain01(String s) { - * name = s; - * } - * public void run() { - * if (name == null) - * System.out.println("A new thread created"); - * else - * System.out.println("A new thread with name " + name + - * " created"); - * } - * } - * class threadtest01 { - * public static void main(String args[] ) { - * int failed = 0 ; - * - * <b>Thread t1 = new Thread();</b> - * if (t1 != null) - * System.out.println("new Thread() succeed"); - * else { - * System.out.println("new Thread() failed"); - * failed++; - * } - * } - * } - * </pre></blockquote> - * - * @see java.lang.Thread#Thread(java.lang.ThreadGroup, - * java.lang.Runnable, java.lang.String) - */ - public Thread() - { - this(null, null, gen_name()); - } - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(null, target,</code> - * <i>gname</i><code>)</code>, where <i>gname</i> is - * a newly generated name. Automatically generated names are of the - * form <code>"Thread-"+</code><i>n</i>, where <i>n</i> is an integer. - * - * @param target the object whose <code>run</code> method is called. - * @see java.lang.Thread#Thread(java.lang.ThreadGroup, - * java.lang.Runnable, java.lang.String) - */ - public Thread(Runnable target) - { - this(null, target, gen_name()); - } - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(null, null, name)</code>. - * - * @param name the name of the new thread. - * @see java.lang.Thread#Thread(java.lang.ThreadGroup, - * java.lang.Runnable, java.lang.String) - */ - public Thread(String name) - { - this(null, null, name); - } - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(group, target,</code> - * <i>gname</i><code>)</code>, where <i>gname</i> is - * a newly generated name. Automatically generated names are of the - * form <code>"Thread-"+</code><i>n</i>, where <i>n</i> is an integer. - * - * @param group the group to put the Thread into - * @param target the Runnable object to execute - * @throws SecurityException if this thread cannot access <code>group</code> - * @throws IllegalThreadStateException if group is destroyed - * @see #Thread(ThreadGroup, Runnable, String) - */ - public Thread(ThreadGroup group, Runnable target) - { - this(group, target, gen_name()); - } - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(group, null, name)</code> - * - * @param group the group to put the Thread into - * @param name the name for the Thread - * @throws NullPointerException if name is null - * @throws SecurityException if this thread cannot access <code>group</code> - * @throws IllegalThreadStateException if group is destroyed - * @see #Thread(ThreadGroup, Runnable, String) - */ - public Thread(ThreadGroup group, String name) - { - this(group, null, name); - } - - /** - * Allocates a new <code>Thread</code> object. This constructor has - * the same effect as <code>Thread(null, target, name)</code>. - * - * @param target the Runnable object to execute - * @param name the name for the Thread - * @throws NullPointerException if name is null - * @see #Thread(ThreadGroup, Runnable, String) - */ - public Thread(Runnable target, String name) - { - this(null, target, name); - } - - /** - * Allocate a new Thread object, with the specified ThreadGroup and name, and - * using the specified Runnable object's <code>run()</code> method to - * execute. If the Runnable object is null, <code>this</code> (which is - * a Runnable) is used instead. - * - * <p>If the ThreadGroup is null, the security manager is checked. If a - * manager exists and returns a non-null object for - * <code>getThreadGroup</code>, that group is used; otherwise the group - * of the creating thread is used. Note that the security manager calls - * <code>checkAccess</code> if the ThreadGroup is not null. - * - * <p>The new Thread will inherit its creator's priority and daemon status. - * These can be changed with <code>setPriority</code> and - * <code>setDaemon</code>. - * - * @param group the group to put the Thread into - * @param target the Runnable object to execute - * @param name the name for the Thread - * @throws NullPointerException if name is null - * @throws SecurityException if this thread cannot access <code>group</code> - * @throws IllegalThreadStateException if group is destroyed - * @see Runnable#run() - * @see #run() - * @see #setDaemon(boolean) - * @see #setPriority(int) - * @see SecurityManager#checkAccess(ThreadGroup) - * @see ThreadGroup#checkAccess() - */ - public Thread(ThreadGroup group, Runnable target, String name) - { - this(currentThread(), group, target, name, false); - } - - /** - * Allocate a new Thread object, as if by - * <code>Thread(group, null, name)</code>, and give it the specified stack - * size, in bytes. The stack size is <b>highly platform independent</b>, - * and the virtual machine is free to round up or down, or ignore it - * completely. A higher value might let you go longer before a - * <code>StackOverflowError</code>, while a lower value might let you go - * longer before an <code>OutOfMemoryError</code>. Or, it may do absolutely - * nothing! So be careful, and expect to need to tune this value if your - * virtual machine even supports it. - * - * @param group the group to put the Thread into - * @param target the Runnable object to execute - * @param name the name for the Thread - * @param size the stack size, in bytes; 0 to be ignored - * @throws NullPointerException if name is null - * @throws SecurityException if this thread cannot access <code>group</code> - * @throws IllegalThreadStateException if group is destroyed - * @since 1.4 - */ - public Thread(ThreadGroup group, Runnable target, String name, long size) - { - // Just ignore stackSize for now. - this(currentThread(), group, target, name, false); - } - - /** - * Allocate a new Thread object for threads used internally to the - * run time. Runtime threads should not be members of an - * application ThreadGroup, nor should they execute arbitrary user - * code as part of the InheritableThreadLocal protocol. - * - * @param name the name for the Thread - * @param noInheritableThreadLocal if true, do not initialize - * InheritableThreadLocal variables for this thread. - * @throws IllegalThreadStateException if group is destroyed - */ - Thread(String name, boolean noInheritableThreadLocal) - { - this(null, null, null, name, noInheritableThreadLocal); - } - - private Thread (Thread current, ThreadGroup g, Runnable r, String n, boolean noInheritableThreadLocal) - { - // Make sure the current thread may create a new thread. - checkAccess(); - - // The Class Libraries book says ``threadName cannot be null''. I - // take this to mean NullPointerException. - if (n == null) - throw new NullPointerException (); - - if (g == null) - { - // If CURRENT is null, then we are bootstrapping the first thread. - // Use ThreadGroup.root, the main threadgroup. - if (current == null) - group = ThreadGroup.root; - else - group = current.getThreadGroup(); - } - else - group = g; - - data = null; - interrupt_flag = false; - startable_flag = true; - - synchronized (Thread.class) - { - this.threadId = nextThreadId++; - } - - // Always create the ThreadLocalMap when creating a thread; the - // previous code did this lazily when getThreadLocals was called, - // but this is a divergence from Classpath's implementation of - // ThreadLocal. - this.locals = new ThreadLocalMap(); - - if (current != null) - { - group.checkAccess(); - - daemon = current.isDaemon(); - int gmax = group.getMaxPriority(); - int pri = current.getPriority(); - priority = (gmax < pri ? gmax : pri); - contextClassLoader = current.contextClassLoader; - // InheritableThreadLocal allows arbitrary user code to be - // executed, only do this if our caller desires it. - if (!noInheritableThreadLocal) - InheritableThreadLocal.newChildThread(this); - } - else - { - daemon = false; - priority = NORM_PRIORITY; - } - - name = n; - group.addThread(this); - runnable = r; - - initialize_native (); - } - - /** - * Get the number of active threads in the current Thread's ThreadGroup. - * This implementation calls - * <code>currentThread().getThreadGroup().activeCount()</code>. - * - * @return the number of active threads in the current ThreadGroup - * @see ThreadGroup#activeCount() - */ - public static int activeCount() - { - return currentThread().group.activeCount(); - } - - /** - * Check whether the current Thread is allowed to modify this Thread. This - * passes the check on to <code>SecurityManager.checkAccess(this)</code>. - * - * @throws SecurityException if the current Thread cannot modify this Thread - * @see SecurityManager#checkAccess(Thread) - */ - public final void checkAccess() - { - SecurityManager sm = System.getSecurityManager(); - if (sm != null) - sm.checkAccess(this); - } - - /** - * Count the number of stack frames in this Thread. The Thread in question - * must be suspended when this occurs. - * - * @return the number of stack frames in this Thread - * @throws IllegalThreadStateException if this Thread is not suspended - * @deprecated pointless, since suspend is deprecated - */ - public native int countStackFrames(); - - /** - * Get the currently executing Thread. In the situation that the - * currently running thread was created by native code and doesn't - * have an associated Thread object yet, a new Thread object is - * constructed and associated with the native thread. - * - * @return the currently executing Thread - */ - public static native Thread currentThread(); - - /** - * Originally intended to destroy this thread, this method was never - * implemented by Sun, and is hence a no-op. - * - * @deprecated This method was originally intended to simply destroy - * the thread without performing any form of cleanup operation. - * However, it was never implemented. It is now deprecated - * for the same reason as <code>suspend()</code>, - * <code>stop()</code> and <code>resume()</code>; namely, - * it is prone to deadlocks. If a thread is destroyed while - * it still maintains a lock on a resource, then this resource - * will remain locked and any attempts by other threads to - * access the resource will result in a deadlock. Thus, even - * an implemented version of this method would be still be - * deprecated, due to its unsafe nature. - * @throws NoSuchMethodError as this method was never implemented. - */ - public void destroy() - { - throw new NoSuchMethodError(); - } - - /** - * Print a stack trace of the current thread to stderr using the same - * format as Throwable's printStackTrace() method. - * - * @see Throwable#printStackTrace() - */ - public static void dumpStack() - { - (new Exception("Stack trace")).printStackTrace(); - } - - /** - * Copy every active thread in the current Thread's ThreadGroup into the - * array. Extra threads are silently ignored. This implementation calls - * <code>getThreadGroup().enumerate(array)</code>, which may have a - * security check, <code>checkAccess(group)</code>. - * - * @param array the array to place the Threads into - * @return the number of Threads placed into the array - * @throws NullPointerException if array is null - * @throws SecurityException if you cannot access the ThreadGroup - * @see ThreadGroup#enumerate(Thread[]) - * @see #activeCount() - * @see SecurityManager#checkAccess(ThreadGroup) - */ - public static int enumerate(Thread[] array) - { - return currentThread().group.enumerate(array); - } - - /** - * Get this Thread's name. - * - * @return this Thread's name - */ - public final String getName() - { - return name; - } - - /** - * Get this Thread's priority. - * - * @return the Thread's priority - */ - public final int getPriority() - { - return priority; - } - - /** - * Get the ThreadGroup this Thread belongs to. If the thread has died, this - * returns null. - * - * @return this Thread's ThreadGroup - */ - public final ThreadGroup getThreadGroup() - { - return group; - } - - /** - * Checks whether the current thread holds the monitor on a given object. - * This allows you to do <code>assert Thread.holdsLock(obj)</code>. - * - * @param obj the object to test lock ownership on. - * @return true if the current thread is currently synchronized on obj - * @throws NullPointerException if obj is null - * @since 1.4 - */ - public static native boolean holdsLock(Object obj); - - /** - * Interrupt this Thread. First, there is a security check, - * <code>checkAccess</code>. Then, depending on the current state of the - * thread, various actions take place: - * - * <p>If the thread is waiting because of {@link #wait()}, - * {@link #sleep(long)}, or {@link #join()}, its <i>interrupt status</i> - * will be cleared, and an InterruptedException will be thrown. Notice that - * this case is only possible if an external thread called interrupt(). - * - * <p>If the thread is blocked in an interruptible I/O operation, in - * {@link java.nio.channels.InterruptibleChannel}, the <i>interrupt - * status</i> will be set, and ClosedByInterruptException will be thrown. - * - * <p>If the thread is blocked on a {@link java.nio.channels.Selector}, the - * <i>interrupt status</i> will be set, and the selection will return, with - * a possible non-zero value, as though by the wakeup() method. - * - * <p>Otherwise, the interrupt status will be set. - * - * @throws SecurityException if you cannot modify this Thread - */ - public native void interrupt(); - - /** - * Determine whether the current Thread has been interrupted, and clear - * the <i>interrupted status</i> in the process. - * - * @return whether the current Thread has been interrupted - * @see #isInterrupted() - */ - public static boolean interrupted() - { - return currentThread().isInterrupted(true); - } - - /** - * Determine whether the given Thread has been interrupted, but leave - * the <i>interrupted status</i> alone in the process. - * - * @return whether the Thread has been interrupted - * @see #interrupted() - */ - public boolean isInterrupted() - { - return interrupt_flag; - } - - /** - * Determine whether this Thread is alive. A thread which is alive has - * started and not yet died. - * - * @return whether this Thread is alive - */ - public final native boolean isAlive(); - - /** - * Tell whether this is a daemon Thread or not. - * - * @return whether this is a daemon Thread or not - * @see #setDaemon(boolean) - */ - public final boolean isDaemon() - { - return daemon; - } - - /** - * Wait forever for the Thread in question to die. - * - * @throws InterruptedException if the Thread is interrupted; it's - * <i>interrupted status</i> will be cleared - */ - public final void join() throws InterruptedException - { - join(0, 0); - } - - /** - * Wait the specified amount of time for the Thread in question to die. - * - * @param ms the number of milliseconds to wait, or 0 for forever - * @throws InterruptedException if the Thread is interrupted; it's - * <i>interrupted status</i> will be cleared - */ - public final void join(long ms) throws InterruptedException - { - join(ms, 0); - } - - /** - * Wait the specified amount of time for the Thread in question to die. - * - * <p>Note that 1,000,000 nanoseconds == 1 millisecond, but most VMs do - * not offer that fine a grain of timing resolution. Besides, there is - * no guarantee that this thread can start up immediately when time expires, - * because some other thread may be active. So don't expect real-time - * performance. - * - * @param ms the number of milliseconds to wait, or 0 for forever - * @param ns the number of extra nanoseconds to sleep (0-999999) - * @throws InterruptedException if the Thread is interrupted; it's - * <i>interrupted status</i> will be cleared - * @throws IllegalArgumentException if ns is invalid - * @XXX A ThreadListener would be nice, to make this efficient. - */ - public final native void join(long ms, int ns) - throws InterruptedException; - - /** - * Resume this Thread. If the thread is not suspended, this method does - * nothing. To mirror suspend(), there may be a security check: - * <code>checkAccess</code>. - * - * @throws SecurityException if you cannot resume the Thread - * @see #checkAccess() - * @see #suspend() - * @deprecated pointless, since suspend is deprecated - */ - public final native void resume(); - - private final native void finish_(); - - /** - * Determine whether the given Thread has been interrupted, but leave - * the <i>interrupted status</i> alone in the process. - * - * @return whether the current Thread has been interrupted - * @see #interrupted() - */ - private boolean isInterrupted(boolean clear_flag) - { - boolean r = interrupt_flag; - if (clear_flag && r) - { - // Only clear the flag if we saw it as set. Otherwise this could - // potentially cause us to miss an interrupt in a race condition, - // because this method is not synchronized. - interrupt_flag = false; - } - return r; - } - - /** - * The method of Thread that will be run if there is no Runnable object - * associated with the Thread. Thread's implementation does nothing at all. - * - * @see #start() - * @see #Thread(ThreadGroup, Runnable, String) - */ - public void run() - { - if (runnable != null) - runnable.run(); - } - - /** - * Set the daemon status of this Thread. If this is a daemon Thread, then - * the VM may exit even if it is still running. This may only be called - * before the Thread starts running. There may be a security check, - * <code>checkAccess</code>. - * - * @param daemon whether this should be a daemon thread or not - * @throws SecurityException if you cannot modify this Thread - * @throws IllegalThreadStateException if the Thread is active - * @see #isDaemon() - * @see #checkAccess() - */ - public final void setDaemon(boolean daemon) - { - if (!startable_flag) - throw new IllegalThreadStateException(); - checkAccess(); - this.daemon = daemon; - } - - /** - * Returns the context classloader of this Thread. The context - * classloader can be used by code that want to load classes depending - * on the current thread. Normally classes are loaded depending on - * the classloader of the current class. There may be a security check - * for <code>RuntimePermission("getClassLoader")</code> if the caller's - * class loader is not null or an ancestor of this thread's context class - * loader. - * - * @return the context class loader - * @throws SecurityException when permission is denied - * @see #setContextClassLoader(ClassLoader) - * @since 1.2 - */ - public synchronized ClassLoader getContextClassLoader() - { - if (contextClassLoader == null) - contextClassLoader = ClassLoader.getSystemClassLoader(); - - // Check if we may get the classloader - SecurityManager sm = System.getSecurityManager(); - if (contextClassLoader != null && sm != null) - { - // Get the calling classloader - ClassLoader cl = VMStackWalker.getCallingClassLoader(); - if (cl != null && !cl.isAncestorOf(contextClassLoader)) - sm.checkPermission(new RuntimePermission("getClassLoader")); - } - return contextClassLoader; - } - - /** - * Sets the context classloader for this Thread. When not explicitly set, - * the context classloader for a thread is the same as the context - * classloader of the thread that created this thread. The first thread has - * as context classloader the system classloader. There may be a security - * check for <code>RuntimePermission("setContextClassLoader")</code>. - * - * @param classloader the new context class loader - * @throws SecurityException when permission is denied - * @see #getContextClassLoader() - * @since 1.2 - */ - public synchronized void setContextClassLoader(ClassLoader classloader) - { - SecurityManager sm = System.getSecurityManager(); - if (sm != null) - sm.checkPermission(new RuntimePermission("setContextClassLoader")); - this.contextClassLoader = classloader; - } - - /** - * Set this Thread's name. There may be a security check, - * <code>checkAccess</code>. - * - * @param name the new name for this Thread - * @throws NullPointerException if name is null - * @throws SecurityException if you cannot modify this Thread - */ - public final void setName(String name) - { - checkAccess(); - // The Class Libraries book says ``threadName cannot be null''. I - // take this to mean NullPointerException. - if (name == null) - throw new NullPointerException(); - this.name = name; - } - - /** - * Yield to another thread. The Thread will not lose any locks it holds - * during this time. There are no guarantees which thread will be - * next to run, and it could even be this one, but most VMs will choose - * the highest priority thread that has been waiting longest. - */ - public static native void yield(); - - /** - * Suspend the current Thread's execution for the specified amount of - * time. The Thread will not lose any locks it has during this time. There - * are no guarantees which thread will be next to run, but most VMs will - * choose the highest priority thread that has been waiting longest. - * - * @param ms the number of milliseconds to sleep, or 0 for forever - * @throws InterruptedException if the Thread is (or was) interrupted; - * it's <i>interrupted status</i> will be cleared - * @throws IllegalArgumentException if ms is negative - * @see #interrupt() - * @see #notify() - * @see #wait(long) - */ - public static void sleep(long ms) throws InterruptedException - { - sleep(ms, 0); - } - - /** - * Suspend the current Thread's execution for the specified amount of - * time. The Thread will not lose any locks it has during this time. There - * are no guarantees which thread will be next to run, but most VMs will - * choose the highest priority thread that has been waiting longest. - * <p> - * Note that 1,000,000 nanoseconds == 1 millisecond, but most VMs - * do not offer that fine a grain of timing resolution. When ms is - * zero and ns is non-zero the Thread will sleep for at least one - * milli second. There is no guarantee that this thread can start up - * immediately when time expires, because some other thread may be - * active. So don't expect real-time performance. - * - * @param ms the number of milliseconds to sleep, or 0 for forever - * @param ns the number of extra nanoseconds to sleep (0-999999) - * @throws InterruptedException if the Thread is (or was) interrupted; - * it's <i>interrupted status</i> will be cleared - * @throws IllegalArgumentException if ms or ns is negative - * or ns is larger than 999999. - * @see #interrupt() - * @see #notify() - * @see #wait(long, int) - */ - public static native void sleep(long timeout, int nanos) - throws InterruptedException; - - /** - * Start this Thread, calling the run() method of the Runnable this Thread - * was created with, or else the run() method of the Thread itself. This - * is the only way to start a new thread; calling run by yourself will just - * stay in the same thread. The virtual machine will remove the thread from - * its thread group when the run() method completes. - * - * @throws IllegalThreadStateException if the thread has already started - * @see #run() - */ - public native void start(); - - /** - * Cause this Thread to stop abnormally because of the throw of a ThreadDeath - * error. If you stop a Thread that has not yet started, it will stop - * immediately when it is actually started. - * - * <p>This is inherently unsafe, as it can interrupt synchronized blocks and - * leave data in bad states. Hence, there is a security check: - * <code>checkAccess(this)</code>, plus another one if the current thread - * is not this: <code>RuntimePermission("stopThread")</code>. If you must - * catch a ThreadDeath, be sure to rethrow it after you have cleaned up. - * ThreadDeath is the only exception which does not print a stack trace when - * the thread dies. - * - * @throws SecurityException if you cannot stop the Thread - * @see #interrupt() - * @see #checkAccess() - * @see #start() - * @see ThreadDeath - * @see ThreadGroup#uncaughtException(Thread, Throwable) - * @see SecurityManager#checkAccess(Thread) - * @see SecurityManager#checkPermission(Permission) - * @deprecated unsafe operation, try not to use - */ - public final void stop() - { - // Argument doesn't matter, because this is no longer - // supported. - stop(null); - } - - /** - * Cause this Thread to stop abnormally and throw the specified exception. - * If you stop a Thread that has not yet started, the stop is ignored - * (contrary to what the JDK documentation says). - * <b>WARNING</b>This bypasses Java security, and can throw a checked - * exception which the call stack is unprepared to handle. Do not abuse - * this power. - * - * <p>This is inherently unsafe, as it can interrupt synchronized blocks and - * leave data in bad states. Hence, there is a security check: - * <code>checkAccess(this)</code>, plus another one if the current thread - * is not this: <code>RuntimePermission("stopThread")</code>. If you must - * catch a ThreadDeath, be sure to rethrow it after you have cleaned up. - * ThreadDeath is the only exception which does not print a stack trace when - * the thread dies. - * - * @param t the Throwable to throw when the Thread dies - * @throws SecurityException if you cannot stop the Thread - * @throws NullPointerException in the calling thread, if t is null - * @see #interrupt() - * @see #checkAccess() - * @see #start() - * @see ThreadDeath - * @see ThreadGroup#uncaughtException(Thread, Throwable) - * @see SecurityManager#checkAccess(Thread) - * @see SecurityManager#checkPermission(Permission) - * @deprecated unsafe operation, try not to use - */ - public final native void stop(Throwable t); - - /** - * Suspend this Thread. It will not come back, ever, unless it is resumed. - * - * <p>This is inherently unsafe, as the suspended thread still holds locks, - * and can potentially deadlock your program. Hence, there is a security - * check: <code>checkAccess</code>. - * - * @throws SecurityException if you cannot suspend the Thread - * @see #checkAccess() - * @see #resume() - * @deprecated unsafe operation, try not to use - */ - public final native void suspend(); - - /** - * Set this Thread's priority. There may be a security check, - * <code>checkAccess</code>, then the priority is set to the smaller of - * priority and the ThreadGroup maximum priority. - * - * @param priority the new priority for this Thread - * @throws IllegalArgumentException if priority exceeds MIN_PRIORITY or - * MAX_PRIORITY - * @throws SecurityException if you cannot modify this Thread - * @see #getPriority() - * @see #checkAccess() - * @see ThreadGroup#getMaxPriority() - * @see #MIN_PRIORITY - * @see #MAX_PRIORITY - */ - public final native void setPriority(int newPriority); - - /** - * Returns a string representation of this thread, including the - * thread's name, priority, and thread group. - * - * @return a human-readable String representing this Thread - */ - public String toString() - { - return ("Thread[" + name + "," + priority + "," - + (group == null ? "" : group.getName()) + "]"); - } - - private final native void initialize_native(); - - private final native static String gen_name(); - - /** - * Returns the map used by ThreadLocal to store the thread local values. - */ - static ThreadLocalMap getThreadLocals() - { - Thread thread = currentThread(); - ThreadLocalMap locals = thread.locals; - - return locals; - } - - /** - * Assigns the given <code>UncaughtExceptionHandler</code> to this - * thread. This will then be called if the thread terminates due - * to an uncaught exception, pre-empting that of the - * <code>ThreadGroup</code>. - * - * @param h the handler to use for this thread. - * @throws SecurityException if the current thread can't modify this thread. - * @since 1.5 - */ - public void setUncaughtExceptionHandler(UncaughtExceptionHandler h) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkAccess(this); - exceptionHandler = h; - } - - /** - * <p> - * Returns the handler used when this thread terminates due to an - * uncaught exception. The handler used is determined by the following: - * </p> - * <ul> - * <li>If this thread has its own handler, this is returned.</li> - * <li>If not, then the handler of the thread's <code>ThreadGroup</code> - * object is returned.</li> - * <li>If both are unavailable, then <code>null</code> is returned - * (which can only happen when the thread was terminated since - * then it won't have an associated thread group anymore).</li> - * </ul> - * - * @return the appropriate <code>UncaughtExceptionHandler</code> or - * <code>null</code> if one can't be obtained. - * @since 1.5 - */ - public UncaughtExceptionHandler getUncaughtExceptionHandler() - { - // FIXME: if thread is dead, should return null... - return exceptionHandler != null ? exceptionHandler : group; - } - - /** - * <p> - * Sets the default uncaught exception handler used when one isn't - * provided by the thread or its associated <code>ThreadGroup</code>. - * This exception handler is used when the thread itself does not - * have an exception handler, and the thread's <code>ThreadGroup</code> - * does not override this default mechanism with its own. As the group - * calls this handler by default, this exception handler should not defer - * to that of the group, as it may lead to infinite recursion. - * </p> - * <p> - * Uncaught exception handlers are used when a thread terminates due to - * an uncaught exception. Replacing this handler allows default code to - * be put in place for all threads in order to handle this eventuality. - * </p> - * - * @param h the new default uncaught exception handler to use. - * @throws SecurityException if a security manager is present and - * disallows the runtime permission - * "setDefaultUncaughtExceptionHandler". - * @since 1.5 - */ - public static void - setDefaultUncaughtExceptionHandler(UncaughtExceptionHandler h) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("setDefaultUncaughtExceptionHandler")); - defaultHandler = h; - } - - /** - * Returns the handler used by default when a thread terminates - * unexpectedly due to an exception, or <code>null</code> if one doesn't - * exist. - * - * @return the default uncaught exception handler. - * @since 1.5 - */ - public static UncaughtExceptionHandler getDefaultUncaughtExceptionHandler() - { - return defaultHandler; - } - - /** - * Returns the unique identifier for this thread. This ID is generated - * on thread creation, and may be re-used on its death. - * - * @return a positive long number representing the thread's ID. - * @since 1.5 - */ - public long getId() - { - return threadId; - } - - /** - * <p> - * This interface is used to handle uncaught exceptions - * which cause a <code>Thread</code> to terminate. When - * a thread, t, is about to terminate due to an uncaught - * exception, the virtual machine looks for a class which - * implements this interface, in order to supply it with - * the dying thread and its uncaught exception. - * </p> - * <p> - * The virtual machine makes two attempts to find an - * appropriate handler for the uncaught exception, in - * the following order: - * </p> - * <ol> - * <li> - * <code>t.getUncaughtExceptionHandler()</code> -- - * the dying thread is queried first for a handler - * specific to that thread. - * </li> - * <li> - * <code>t.getThreadGroup()</code> -- - * the thread group of the dying thread is used to - * handle the exception. If the thread group has - * no special requirements for handling the exception, - * it may simply forward it on to - * <code>Thread.getDefaultUncaughtExceptionHandler()</code>, - * the default handler, which is used as a last resort. - * </li> - * </ol> - * <p> - * The first handler found is the one used to handle - * the uncaught exception. - * </p> - * - * @author Tom Tromey <tromey@redhat.com> - * @author Andrew John Hughes <gnu_andrew@member.fsf.org> - * @since 1.5 - * @see Thread#getUncaughtExceptionHandler() - * @see Thread#setUncaughtExceptionHandler(UncaughtExceptionHandler) - * @see Thread#getDefaultUncaughtExceptionHandler() - * @see - * Thread#setDefaultUncaughtExceptionHandler(java.lang.Thread.UncaughtExceptionHandler) - */ - public interface UncaughtExceptionHandler - { - /** - * Invoked by the virtual machine with the dying thread - * and the uncaught exception. Any exceptions thrown - * by this method are simply ignored by the virtual - * machine. - * - * @param thr the dying thread. - * @param exc the uncaught exception. - */ - void uncaughtException(Thread thr, Throwable exc); - } - - /** - * <p> - * Represents the current state of a thread, according to the VM rather - * than the operating system. It can be one of the following: - * </p> - * <ul> - * <li>NEW -- The thread has just been created but is not yet running.</li> - * <li>RUNNABLE -- The thread is currently running or can be scheduled - * to run.</li> - * <li>BLOCKED -- The thread is blocked waiting on an I/O operation - * or to obtain a lock.</li> - * <li>WAITING -- The thread is waiting indefinitely for another thread - * to do something.</li> - * <li>TIMED_WAITING -- The thread is waiting for a specific amount of time - * for another thread to do something.</li> - * <li>TERMINATED -- The thread has exited.</li> - * </ul> - * - * @since 1.5 - */ - public enum State - { - BLOCKED, NEW, RUNNABLE, TERMINATED, TIMED_WAITING, WAITING; - } - - - /** - * Returns the current state of the thread. This - * is designed for monitoring thread behaviour, rather - * than for synchronization control. - * - * @return the current thread state. - */ - public native State getState(); - - /** - * <p> - * Returns a map of threads to stack traces for each - * live thread. The keys of the map are {@link Thread} - * objects, which map to arrays of {@link StackTraceElement}s. - * The results obtained from Calling this method are - * equivalent to calling {@link getStackTrace()} on each - * thread in succession. Threads may be executing while - * this takes place, and the results represent a snapshot - * of the thread at the time its {@link getStackTrace()} - * method is called. - * </p> - * <p> - * The stack trace information contains the methods called - * by the thread, with the most recent method forming the - * first element in the array. The array will be empty - * if the virtual machine can not obtain information on the - * thread. - * </p> - * <p> - * To execute this method, the current security manager - * (if one exists) must allow both the - * <code>"getStackTrace"</code> and - * <code>"modifyThreadGroup"</code> {@link RuntimePermission}s. - * </p> - * - * @return a map of threads to arrays of {@link StackTraceElement}s. - * @throws SecurityException if a security manager exists, and - * prevents either or both the runtime - * permissions specified above. - * @since 1.5 - * @see #getStackTrace() - */ - public static Map<Thread, StackTraceElement[]> getAllStackTraces() - { - ThreadGroup group = currentThread().group; - while (group.getParent() != null) - group = group.getParent(); - int arraySize = group.activeCount(); - Thread[] threadList = new Thread[arraySize]; - int filled = group.enumerate(threadList); - while (filled == arraySize) - { - arraySize *= 2; - threadList = new Thread[arraySize]; - filled = group.enumerate(threadList); - } - Map traces = new HashMap(); - for (int a = 0; a < filled; ++a) - traces.put(threadList[a], - threadList[a].getStackTrace()); - return traces; - } - - /** - * <p> - * Returns an array of {@link StackTraceElement}s - * representing the current stack trace of this thread. - * The first element of the array is the most recent - * method called, and represents the top of the stack. - * The elements continue in this order, with the last - * element representing the bottom of the stack. - * </p> - * <p> - * A zero element array is returned for threads which - * have not yet started (and thus have not yet executed - * any methods) or for those which have terminated. - * Where the virtual machine can not obtain a trace for - * the thread, an empty array is also returned. The - * virtual machine may also omit some methods from the - * trace in non-zero arrays. - * </p> - * <p> - * To execute this method, the current security manager - * (if one exists) must allow both the - * <code>"getStackTrace"</code> and - * <code>"modifyThreadGroup"</code> {@link RuntimePermission}s. - * </p> - * - * @return a stack trace for this thread. - * @throws SecurityException if a security manager exists, and - * prevents the use of the - * <code>"getStackTrace"</code> - * permission. - * @since 1.5 - * @see #getAllStackTraces() - */ - public StackTraceElement[] getStackTrace() - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("getStackTrace")); - - // Calling java.lang.management via reflection means that - // javax.management be overridden in the endorsed directory. - - // This is the equivalent code: - // - // ThreadMXBean bean = ManagementFactory.getThreadMXBean(); - // ThreadInfo info = bean.getThreadInfo(getId(), Integer.MAX_VALUE); - // return info.getStackTrace(); - - try - { - try - { - Object bean - = (Class.forName("java.lang.management.ManagementFactory") - .getDeclaredMethod("getThreadMXBean") - .invoke(null)); - Object info = bean.getClass() - .getDeclaredMethod("getThreadInfo", long.class, int.class) - .invoke(bean, new Long(getId()), new Integer(Integer.MAX_VALUE)); - Object trace = info.getClass() - .getDeclaredMethod("getStackTrace").invoke(info); - return (StackTraceElement[])trace; - } - catch (InvocationTargetException e) - { - throw (Exception)e.getTargetException(); - } - } - catch (UnsupportedOperationException e) - { - throw e; - } - catch (Exception e) - { - throw new UnsupportedOperationException(e); - } - } -} |